Crimped tow deregistration apparatus



Nov. s, 196s p. M. COLE 3,408,696

CRIMPED TOW DEREGISTRATION APPARATUS Filed July 2o, 1967 5 sheets-sheet z v L-ii.

lINVENT OR a M C045,

Nov. 5, 1968 .P. M. COLE y CRIMPED TOW DEREGSTRTION APPARATUS Filed July 20, 1967 3 Sheets-Sheet 3 INVENTOR pa M co;

United States Patent Office 3,408,696 Patented Nov. 5, 1568 3,408,696 CRIMPED TOW DEREGISTRATION APPARATUS Paul M. Cole, Wilmington, Del., assignor to E. I. du Pont ydevNemours and Company, Wilmington, Del., a corporation of Delaware Filed July 20, 1967, Ser. No. 654,891

l Claims. (Cl. 19-65) ABSTRACT OF THE DISCLOSURE BACKGROUND OF i THE INVENTION Field 0f the invention This invention relates to treatment of filamentary tows, and more particularly to a novel apparatus for deregistering filaments in a crimped tow, i.e., to move crimps in adjacent filaments out of phase with each other.

Description of the prior art Several methods have been used in the past for opening,` bulking or spreading filamentary tows. Most techniques have been directed to convertin-g a tow of relatively high density of filaments to one of relatively low density of filaments. More recently, attention has been directed to the opening and more particularly to the separation within the tow bundle of crimped filaments which are closely spaced and in phase with the crimps in adjacent filaments. The openedy and separated tow is not only of lower density than the original tow, but also most of `the crimped filaments have been displaced longitudinally with respect to adjacent filaments so that adjacent crimps are out of phase with each other. This operation Will be designated herein as deregistration of the crimped filaments; i.e., displacing neighboring crimped filaments so that adjacent filaments no longer have crimps which are in phase with each other. The term deregistration as used herein is not intended to convey any particular degree of perfection with respect to this displacement of neighboring crimps. Naturally, most uses for the deregistered tows will be optimizedwhen a high proportion of the crimped filaments in a given tow bundle have had their crimps displaced out of phase, when the treated tow is stable and when the crimps `do not return to the original densitied and in-phase registry.

SUMMARY OF INVENTION l In accordance with the present invention there i-s provided a process for deregistering a continuous crimped filamentary tow comprising the steps of longitudinally forwarding the tow from a supply zone, through a snub zone and-subsequently to a take-up zone, longitudinally tensioning the tow between the supply zone and the take-up zone, and deregistering the tow within the snubbing zone by sequentially restraining and immediately thereafter allowing free longitudinal motion of the individual filaments of the tow across the lateral dimension of the tow. This process is accomplished by an apparatus comprising a first forwarding means for forwarding the tow in longitudinal direction, a second forwarding means for forwarding the tow after deregistration has been accomplished and for maintaining longitudinal tension upon the tow between the `first and second forwarding means. A plurality ofv discs is rotatably mounted on a traversing means intermediatethe first and second forwarding means. The traversing means is adapted to continuously traverse the discs angularly across the longitudinal dimension of the tow causin-g a portion of the periphery of at lea-st one of the discs to maintain constant rolling contact with the tow. A surface means is operably associated with the plurality of discs to provide in cooperation with the discs a longitudinal drag component upon the individual crimped fibers contacted by the disc as the tow is advanced in a longitudinal direction between surface means and the discs.

BRIEF DESCRIPTION OF DRAWINGS Reference to the accompanying Jdrawings will facilitate an understanding 0f the instant invention.

FIGURE 1 is a schematic view of a typical snubbing element mounted on a roller chain for driving the rolling snubbing elements across a tow.

FIGURE 2 illustrates section A-A of FIGURE l.

FIGURE 3 is a schematic view of an alternative means yfor applying snubbing action to a tow using a deformable roll.

FIGURE 4 is a schematic view of another alternative means Ifor applying snubbing action to a tow in the absence of any solid backing surface against which the snubbing element can be forced.

FIGURE 5 is a schematic view of another means of applying snubbing action to a tow in contact with a nonrotating solid surface.

FIGURE 6 is a schematic view of another means for applying snubbing action to a tow, employing a rotating cylindrical surface in contact with said tow at the point of applied snubbing action, in combination with rounded edges on the surface openings of the slot receiving the snubbing element.

DESCRIPTION OF PREFERRED EMBODIMENTS One -deregistration device constructed in accordance with the instant invention is that shown in FIGURES 1 and 2, in which rollers used as snubbing element 1 are rotatably mounted on -shafts 11 (FIG. 3) carried by the links of a standard roller chain 2 running in track 4. A roll 7 having a rigid supporting surface 8 is mounted by pivoting the roll a'bout a shaft 6 which is counterweighted to bias the roll 7 against the tow 3 and snubbing element 1, with no depression in surface 8.

FIGURE 3 illustrates the use of a 0.615 inch outside diameter disc 10 as the snubbing element with a 0.031 inch edge radius in contact with a supporting surface 13. The surface 13 in this instance is in the form of a roll having a resilient surface. Snubbing is aided by the depression of surface 13 at point 15. Good snubbing action has been obtained also in experiments using a synthetic rubber composition of durometer hardness and a loading of only one ounce per disc 10 making no significant depression in the supporting surface 13. The loading is controlled by pivoting the roller 14 about a parallel axis (not shown) and supplying a counterweight bias upwardly against the tow. The snubbing which takes place without depression of supporting surface 13, as shown in FIGURE l, can be accounted for by the resilient nature of the tow 2. (Even a light load, in such cases, when applied by a thin disc, causes an abrupt change in tow thickness which causes filaments to undergo a pronounced change of direction as they pass under the disc.) In the embodiment of FIGURE 3, roll 14 and surface 13 are cylindrical and means for slow or periodic rotation are provided to distribute wear across surface 13.

Another form of deregistration apparatus is illustrated in FIGURE 4 in which rolling snub 20 does not contact a supporting surface. The supporting surface is replaced with an auxiliary directional device 23,V having a pair of h stationary channel arms 21 and 22 that are parallel to the path of disc 20, one arm being located on each side of the disc path. Back-up devicev23 although longitudinally stationary is biased upwardly. The elevation of the top of arms 21 and 22 is higher than the lowest point of disc periphery so that each disc in passing across the tow 25 depresses the filaments downwardly in passage across 21. This depression causes a filament in contact with each disc 20 at any instant to undergo changes in direction at the top of arm 21, at the bottom of disc 20 and at the top of arm 22. Each of these changes `in direction amount to about 10. These changes in direction produce a temporary` filament drag which increases the tension on the subject filament above that of neighboring filaments, which in turn can pass straight over arms 21 and 22 between disc 20 without snubbing action. The resulting tension differentials cause relative longitudinal displacement of crimps in adjacent filaments. The arms 21 and 22 are typically provided by an aluminum channel that has sufficient depth and width so that no contact is made with the disc 20.

FIGURE 5 shows a modification for deregistering tow very similar to that shown in FIGURE 4, except that in the former there is employed a supporting surface 34 composed of a polyurethane resin. Feed rolls 36 forward the tow 35 to the snubbing device. Pull rolls 37 take the tow 35 from the snubbing device and forward it to a subsequent process step while maintaining longitudinal tension in the tow between the feed rolls and the pull rolls.

Another modification of the invention is illustrated in FIGURE 6. A directional device 51 in the form of a plate with a slotted opening is mounted above a cylindrical supporting surface 52 composed of rigid elastomericmaterial, the slot beingxlocated directly over the center line of the cylinder 53. The surface 52 and directional device 51 are biased upwardly so that the surface 52 presses against the snubbing element 50. The snubbing element passes through the slot without touching the plate 51, the rounded edges 54 of the plate 51 serving as directional changing members. Extremely small vertical forces on the tow 55 at the contact between snubbing element 50 and supporting surface 52 can produce high tension differentials across the tow 55.

The snubbing element of this invention which is in rolling contact across the tow will normally be a rigid wheel, disc, or other rotatable means. The snubbing element is designed to momentarily slow down individual filaments in the tow by pressure against the curved surface of the element without cutting or otherwise damaging the tow.

The snubbing elements may vary in diameter and width, k

and may be made of different materials (e.g., metal, plastic, rubber, glass, ceramic, etc.) giving curved surfaces designed to provide different frictional forces when in rolling contact with the tow. The element may be mounted so that the rolling action across the tow is accomplished either by a positive drive or by a friction drive. The snubbing element causes each single filament, momentarily caught in contact with the curved surface of the element, to undergo two abrupt changes in forward motion. This action provides differential dragging action on neighboring filaments in the tow sufficient to permit dephasing of the crimp by actual displacement of the neighboring filaments.

In order for the snubbing element to accomplish the function of causing at least two abrupt changes in filament direction, the snubbing element must be used with at least one other device for accomplishing deregistration. Either an auxiliary directional device, such as channel 23, or a supporting surface, such as roll 8, can be used with the snubbing element. Alternatively, both a channel and a roll can be used together in conjunction with the snubbing element, a variation of which is illustrated in FIGURE 6. The snubbing element will not perform satisfactorily without having at least one of these auxiliary devices. It is obvious that both the directional device and supporting surface will be duplicated as many times in one operation as ",4-l v. .-1 i. there are snubbing elements to accompany them. Archannel directional device is used with a'snubbin'g element to produce abrupt changes in direction of a given filament in the tow. One or more arms having rounded or smooth surfaces can be used as the auxiliary directional device. Typical channel devices are illustrated in FIGURES 4, 5 and 6. The other auxiliarytdevice which can be used with a snubbing element is a` supporting' surface. Illustrations of typical supporting surfaces are shown in FIGURES 1, 2, 3, 5 and 6. The supporting surfaceis usually mounted beneath the snubbing element on a separate mounting means which serves to bias or force the surface up against the snubbing element and` thereby causethese two elements to effectuate a momentary drag on an individual filament in the tow. The supporting surface may be in the shape of a roll, or it may be in the form of a flat'or rounded platen or a plate. The composition of the support'- ing surface may be selected from any suitable material (e.g., metal, glass, ceramic, plastic, rubber) such that the surface is either resilient (deformable) or rigid (incompressible). h

The following example describes the'method of operation of one of the preferred embodiments. The dimensions and operating parameters are not intended to be restrictive in scope, but are intended to exemplify the invention.

EXAMPLE Referring to one preferred modification illustrated in FIGURE 5, 50,000 denier tow 35, heat set at 216 C. of helically crimped polyester fiber 0f four denier per filament, that has been spread to a 7.75 inches width, is fed at 87.5 feet per minute to the deregistering device of FIGURE 5 at a distance of 12 inches from a set of tow feeding rolls (not illustrated). Snubbing elements 30 in the form of brass rollers of 0.835 inch diameter and 0.125 inch edge radius are carried by conventional roller chain (such as shown in FIGURE 2) at 1.25 inch spacing across the tow 35 at a speed of 62.5 feet per minute. The filaments are depressed 0.094 inch by snubbing engagements with rollers 30, channel arms 31 and 32, and supporting surface 34. The surface 34 is made of a polyurethane resin having a durometer hardness of 95. The auxiliary directional device is constructed of aluminum channel 33 and channel arms 31 and 32. Arms 31 and 32 each have a thickness of 0.094 inch and they have a spacing of 0.312 inch between them. The directional device 33 is biased against the rollers 30 to provide a calculated load of 1.9 pounds per roller. The tow 35 is tensioned by pull rolls (not shown) driven at 110.5 feet per minute at a distance of 63 inches from directional device 3. The tow which originally had an extensive number of filaments in crimp registry is noted to be almost free of such registr after passing through the apparatus. i

STATEMENT OF UTILITY The process and apparatus of this invention is particularly useful, in the processing of light or heavy vdenier tows, for deregistration of crimped filaments. Such tows may have a total tow denier varying from 1,000 up to 1,000,000, and even higher. The snubbing action of this invention serves to deregister the crimped tow more efficiently and more completely when applied to tows that have already been spread to thin webs. The invention may be applied to the deregistration of tows composed of either natural or synthetic filaments, or blends thereof. The tows which will normally be crimped may possess a mechanical crimp, such as the conventional zigzag crimp, or they may contain a three-dimensional crimp, such as the known helical crimp, random crimp, and the ilke. The rolling snubbing action applied to the tow is especially suitable for deregistration of the filaments therein for subsequent treatment with liquids, resins, or the like by dipping or spraying in a solution, dispersion, or emulsion of a resinous or elastomeric binder. When small amounts of such resins are applied to the deregistered tow, the resulting resin-treated tows, after drying and cutting into staple, may be subsequently carded in order to produce a more `uniform web for subsequent textile processing.

A particular advantage of the present invention is that it permits the deregistration of very wide tows which are of progressively greater interest to industry. There is no limit to the width of tow which can be treated. The invention provides essentially uniform snubbing action on the fibers lprogressively across the full width of the tow, producing deregistered tows having more uniform and reproducible properties for subsequent uses.

The foregoing specilication is intended to set forth the invention which is dened and limited only by the annexed claims. Many alternatives and equivalents may be effected by one skilled in the art without deviating from the spirit of the invention.

What is claimed is:

1. An apparatus for deregistration of a continuous crimped lamentary tow comprising:

irst forwarding means for forwarding said tow in a longitudinal direction,

second forwarding means for forwarding said tow after deregistration has been accomplished and for maintaining longitudinal tension upon said tow between said rst and said second forwarding means,

a plurality of discs rotatably mounted on a traversing means intermediate said first and second forwarding means, said traversing means adapted to continually traverse said discs angularly across the longitudinal dimension of said tow causing a portion of the periphery of at least one of said discs to maintain constant rolling contact with said tow,

surface means operably associated with Said plurality of discs to provide in cooperation with said discs, a longitudinal drag component upon the individual crimped bers contacted by said disc as said tow is advanced in said longitudinal direction between said surface means and said discs.

2. The apparatus of claim 1 wherein said surface means is a roll rotatably mounted in relation to said plurality of discs, the axis of said roll mounted parallel to a plane de lined by said discs.

3. The apparatus of claim 2, said roll having a resilient surface capable of deformation by said plurality of discs as they traverse across the longitudinal dimension of said tow.

4. The apparatus of claim 1 wherein said surface means is a channel member having two sides, said member mounted in parallel relation to the path defined by the traverse of said plurality of discs, a portion of the periphery of said traversing discs extending between said sides.

5. The apparatus of claim 4, said channel filled with a resilient substance which contacts the portion of said discs extending inside said channel.

References Cited UNITED STATES PATENTS 3,016,581 1/1962 S-mith. 3,032,829 5/1962 Mahoney et al. 3,156,016 1l/1964 Dunlap et al.

MERVIN STEIN, Primary Examiner.

l. C. WADDEY, Assismnt Exmniner. 

